Adjustable shutter



March 31, 1925.

W. ELLWOOD ADJUSTABLE SHUTTER Filed April 26 1921 gwuamtoz Patented Mar.31, 1925.

UNITED STATES PATENT OFFICE.

WILLIAM EDLWOOD, OF HEMPSTEAD, NEW YORK, ASSIGNOR TO NICHOLAS POWERCOMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

ADJU STABLE SHUTTER.

Application filed April 28, 1921; Serial No. 484,592.

To all whom it may concern:

Be'it known that 1, WILLIAM ELLwooo, a citizen of the United States,residing at Hempstead, 1n the county of Nassau, State of New York, haveinvented certain new and useful Improvements in Adjustable Shutters; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it apper tains to make and use the same.

This invention relates to shutter adjusting devices for motion picturemachines, and has for its object primarily to provide an attachmentwhich may be applied to certain types of machines now on the marketwithout change in construction of the machine, and without the use ofspecial tools other than those ordinarily found in the kit of a movingpicture machine operator.v

A further object of the invention is to provide a device of thischaracter which is of simple and easy operation and of low manufacturingcost, so that it may be readily sold as an accessory to users of motionpicture machines. 7

In the accompanying drawings I have illustrated a preferred embodimentof my shutter adjusting attachment applied to a well known type ofmachine, known to the trade as Powers cameragraph and described in U. S.Letters Patent No. 1,184,126, issued to Nicholas Power on May 23, 1916,and it is for use in conjunction with this type of machine that myimprovement is particularly adapted.

In said drawings,

Figure 1 is a side elevation of the machine showing the shutter supportand driving gears therefor with my adjusting device applied thereto;

Fig. 2 is a similar elevation of the other side of the machine showingthe adjusting device in greater detail;

Fig. 3 is an elevational View of a modified form of my adjusting device;

Fig. 4 is a plan view; and

Fig. 5 is a horizontal sectional view taken on line 55 of Fig. 4.

Referring to the drawings, 1 indicates the frame of the machine which issupplied with the usual film-feeding devices, not shown, but supportedwith their driving gears on rotating shafts mounted in the machineframe, two of which shafts are 'shown' at 2 and 3, respectively, in thedraw ings. The driving mechanism of the machine also embodies a shutterdriving shaft 4 supported for continuous rotation in the machine frameand driving the shutter supporting shaft 5 through a spiral gear 6 andspiral pinion 7. The pinion 7 is attached to the shutter shaft 5 which,in the machine above mentioned, is supported on a bracket 8 attached tothe machine frame and pro jecting beyond the front wall thereof in orderto position the shutter in front of the lens tube 9 which supports theprojecting lenses. i

The shutter is held fast to the shaft by means of a clamping bolt 10 andset screw 11 in the usual manner, the set screw worklng in a keywa-y inthe shutter shaft so that when the shutter is removed for packing it maybe replaced by the operator in correct position to insure the wing ofthe shutter cutting oif the light during the interval of motion of thefilm.

The above described 'construction is that of the present commercialmachine and the adjustment of the shutter, shaft is fixed when themachine is assembled at the factory and can only be altered bydisengaging the gear and pinion 6 and 7 and re-engaging their teeth tosecure a different timed relation of the shutter.

As is well known, it is desirable to have the shutter blade as narrow aspossible consistent with covering the entire movement of the film, inorder that as much light as possible may reach the screen. With a newmachine the shutter blade need be very little wider than theoreticallynecessary, as determined bv the relation of movement and rest of thefilm, but in practice it is not possible to avoid some lost motion inthe gears, and as the machine wears the lost motion increases, therebyrequiring a wider shutter to cover the period of film movement thanwould be necessary if the shutter were capable of slight adjustment tocompensate for the lag resulting from the lost motion.

Devices have heretofore been proposed for securing the proper adjustmentof the shutter with respect to its shaft while the machine is inoperation, but all such devices of which I am aware must either be builtinto the machine or are too bulk an complicated to make their usealtogether desirable.

The object of my present invention has been, therefore, to provide ashutter adj usting device which is readily attached to existing machinesand which avoids complicated and cumbersome parts of prior structures.

My improved attachment comprises primarily an adjusting screw 12 havinga knurled head to facilitate its rotation and a screw threaded part 13which is threaded through a collar 14 designed to be attached to theinner face of the supporting bracket 8. The collar 14 is simply a screweye having its ring threaded to fit the thread 13 and a shank screwedinto a hole tapped in the rear face of the bracket. this constructionbeing employed to permit the slight angular movement of the screwresulting from the movement of the bell crank lever 15 through which theshutter shaft is adjusted.

The bell crank 15 is attached, to the bracket by means ofa pivot' screw16 screwed in a hole tapped in the face of the bracket and atits upperend is provided with a pin 17 engaging a grooved collar 18 attached tothe shutter shaft in the open space ofthe bracket between the pinion 7and the outer shaft hearing. The hori-- zontal arm of the bell cranklever is connected to the lower end of the adjusting screw 12. In thedrawing this connection is shown as consisting of a sleeve 19 slippedover the reduced end of the screw 12 below its threaded portion andserving as an abutment for a collar or screw eye 20 projecting from theside of the arm 15 of the bell crank and adapted to turn slightly in itsthread as necessitated by the angular movement of the screw 12; Thecollar 20 is clamped between the sleeve 19 and the clamping nuts 21threaded on'the' end of the screw 12.

The shank of the screw 12 above the threaded portion 13 is long enoughto bring the knob into position to be readily turned by the operator.\Vhen the knob is turned in one direction or the other the shutter shaft5 will be adjusted longitudinally in its bearings and as the pinion 7 isfast to the shaft the pinion will be adjusted with relation to itscooperating gear 6 whereby the inter-engaging spiral teeth of the pinionand gear will effect a slight rotary adjustment of the shutter shaft 5in a direction depending upon the longitudinal adjustment of the shafteffected by the adjusting screw.

By this arrangement, as the, machine wears and begins to show aso-called travel ghost due to the movement of the film not 'beingcompletely obscured, the operator may slightly adjust the shutter in themanner described to counteract the lag'resulting from the lost motion inthe driving connections and thereby maintain the proper synchronousoperation of the film and shutter.

It .will be observed that the parts necessary to convert the ordinarynon-adjustable shutter into one of the adjustable type are few and areof simple, cheap construction, comprising only the adjusting screw, thebell crank and the collar 18 and their supporting and connecting parts,the spiral gears through which the adjustment is effected beinguniversally employed in ma chines of this type for insuring a quietoperation of the machine. The attachment of the device to existingmachines is very simple, requiringmerely the tapping of two small screwholes into the rear face of the shutter bracket 8 which is usually ofbrass or other soft metal. The actual location of the screw holes in thebracket is not essential, as the collar 18 is held to the shutter shaftby a small set screw which may be positioned at any point along theshutter shaft necessary for proper operation of the adjusting screw. Thescrew eyes 14 form simple and efiicient rocking connections for theadjusting screw 12, the adjustment of which does not require sufficientfrequency to necessitate expensive swiveled supports, etc., although ofcourse it is obvious that such supports may be employed in lieu ofsimple screw eyes, if desired.

In Figs. 3 to 5 I have illustrated a modified form of my adjustingdevice. The supporting bracket 8, in addition to affording a bearing forthe shutter shaft 5, is provided with a pair of outstanding lugs 22having holes at their outer ends to receive the adjusting rod 12.portion of the rod 12 lies between the inner faces of lugs 22, and therod is restrained from longitudinal movement but is free to be rotatedat the will of the operator. Surrounding the threaded portion of thescrew shank is a cooperating threaded sleeve 23 which may be split atone side and brought The screw threaded into engaging relation with thescrew threads by means of a clamping bolt or screw as shown. This sleeve23 forms the outer portion of a member 25 which is provided at its innerend with a tongue or fork 26 adapted to engage in the groove of thecollar 18 secured to the shutter shaft 5. Rotation of the adjustingscrew 12 will thus efiect longitudinal movement of member 25 through themedium of the screw threaded collar 23 and will consequently shift theshutter shaft 5 longitudinally in a direction depending upon thedirection of rotation of the screw 12*. To prevent the screw binding inthe sleeve 23 a rod 27 is secured between lugs 28 and serves as abearingupon which the member 25 is fitted to slide.

Longitudinal adjustment of the shutter shaft 5 effects rotativeadjustment of the shutter through the spiral gear 6 and pinion 7 in themanner already described.

In the particular machine above mentioned the supporting bracket 8 issecured to the frame of the apparatus by rotatively mounting it upon thebearing shutter driving shaft 4 and by providing at its upper edge aslot 28 adapted to fit over a pin or screw 29 to hold it into properposition. In packing the machine for shipment the shutter is removedfrom its shaft and the pin 29 loosened, after which'it is possible toturn the bracket 8 about the shaft- 4 as an axis so that the shuttershaft will lie close to the frame of the apparatus instead of projectingout beyond it as is the case when the parts are in operative position.In my present improvement the entire adjustin mechanism turns with theshutter bracket when the machine is packed and does not interfere in theleast with the other parts ofthe machine. a

In applying/the form of device illustrated in Fi s. 3, 4 and 5 toexisting machines,.a

new s utter bracket with the shutter shaft and adjusting parts assembledthereon can be quickly substituted for the shutter bracket and attachedparts already on the machine. This feature is desirable in that itfacilitates shipment and minimizes the danger of breakage due toprojecting parts being bent or broken.

It is also to be understood that 'my proposed shutter adjusting devicemay be otherwise modified in its details without departprojector,

ing from the spirit of the invention or the scope of the appendedclaims.

I claim:

1. In a picture projector comprising driv-' ingmechanism and a shutteractuated there from, a detachable bracket mounted on said and meanscarried by said bracket for shifting the shutter shaft longitudinally tothereby alter the driving relation of certain of the shutter drivingmember and thus rotatively adjust said shutter relative to the drivingmechanism.

2. In a picture projector comprising driving mechanism, a bracketsecured to the frame of said projector, a rotating shutter supported bysaid bracket, connections between the shutter and driving mechanism, andmeans carried by saidbracket for bodily shifting the shutter drivingshaft to thereby rotatively adjust the shutter relative to the drivingmechanism thru the medium of the gearing of said mechanism.

3. In a picture projector having a projector' a erture, a rotatingshutter havinga shaft, riving mechanism therefor, and means forrotatively adjusting said shutter exterior 0 relative to its drivingmechanism, said means comprising a thumb screw at the extenor of the proector and connections between said thumb screw and the shutter shaft toeffect bodily movement of the shaft.

4. In a picture projector, a bracket at the exterior of the projector, ashutter having a shaft rotatively mounted in said bracket, drivingmechanism for said shaft, and means for adjusting said shutter relativeto the driving mechanism, said means comprising a thumb screw carried bysaid bracket, a collar secured to the shutter shaft, and a memberconnecting said thumb screw with the shaft to thereby provide forshifting said shaft longitudinally and effecting a relative displacementof certain of the shutter driving elements.

5. In a picture projector, a bracket at the exterior of the projector, ashutter having a shaft rotatively mounted in said bracket, a spiralpinion on said shaft, a spiral driving gear cooperating with saidpinion, and

member movable parallel to the axis of thethumb screw and actuatedthereby for transformin rotative motion of the screw into longitu inalmovement of the shutter shaft.

7. In a icture projector, a bracket at the exterior o the projector,shaft rotatively mounted in said bracket, a spiral pinion on said shaft,a spiral driving gear cooperating with said pinion, a thumb vided on theshutter shaft, and a reciprocating member engaging said collar and saidthumb screw for transforming rotative motion of the screw intolongitudinal movement of the shutter shaft.

8. In a picture projector, a bracket at the the rojector, a shutterhaving a shaft rotativel y mounted in said bracket, a spiral pinion onsaid shaft, a spiral driving ear cooperatin with said pinion, a thumscrew mounte in said bracket, a collar provided on the shutter shaft, abearing rod in parallelism with said shaft, and a member slidable onsaid rod adapted to transform rotative motion of the screw intolongitudinal movement of the shutter shaft. In testimony whereof I afiixmy signature.

' WILLIAM ELLWOOD.

a shutter having a 105 screw mounted in said bracket. a collar pro- 7

